This article was originally published in the May/June 1994 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.

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Home Energy Magazine Online May/June 1994

TRENDSDo Refrigerator Thermostat Setups Save Energy?

In its February 1994 issue, Consumer Reports described tests performed on a collection of upscale refrigerators. One feature tested was energy use. The test procedure differed from the one the U.S. Department of Energy (DOE) uses to rate refrigerators, however, because the freezer temperature setting was 5deg.F lower in the Consumer Reports tests.

Since a refrigerator's energy consumption is quite sensitive to temperature settings--both inside the refrigerator and in the kitchen, garage, or basement--the energy use measured by Consumer Reports was higher than that shown on the DOE labels. Thanks to Consumer Reports' measurements, Home Energy can now answer a frequently asked question: How much does the setting affect energy use in typical refrigerators?

The results are surprisingly consistent. Lowering the freezer temperature by 5deg.F increases energy use by an average of 18% (see Figure 1). The increase is slightly larger for top freezers (22%). That translates into an average annual electricity increase of 133 kWh.

Unfortunately, both the DOE and Consumer Reports' test procedures do not realistically portray actual operating conditions. (The units are tested with doors closed in a 90deg.F room for 24 hours.) But energy savings from raising the refrigerator thermostat setting are probably at least 100 kWh per year for the large refrigerators that were tested. Of course, any thermostat setup should be done cautiously. Sometimes refrigerators are set colder than they need to be, but a too-warm setting can lead to spoilage and other food safety problems. The best first strategy is to ensure that the refrigerator is adequately ventilated and kept in as cool a place as possible.

Consumer Reports also delved into setting ease, temperature uniformity, stability, icemaker quality and so on. One finding was that energy costs decline as the overall quality of refrigerators rises. Another was that the more complicated the refrigerator is, the more likely it is to break down: basic refrigerators that lacked through-the-door ice and water dispensers needed fewer repairs than models with those features. Yet another finding was that the world's most efficient Sun Frost RF-19 used roughly the same amount of electricity as the most efficient conventional top-freezer model--the Amana TZ21R2--but at a cost of $3,015, compared to $770.